NSF/GEO-NERC: Collaborative Research: Multi-scale investigation of rheology and emplacement of multi-phase lava

Lava flows displace communities, destroy homes and infrastructure, and can pose a serious hazard to life and health. Accurate forecasting of lava flow emplacement is essential to hazard mitigation and management, and requires a level of understanding of the physical properties of lava which is not currently available. This project will focus on improving this understanding by examining the 2018 eruption of Kilauea volcano, in Hawai'i. This large eruption took place on the lower east rift zone, and was significant in its large volume, fast speeds, and large fraction of gas bubbles. A unique aspect of this eruption is also the unprecedented volume of high-quality direct observations of in-situ flow, including high-resolution videos of flowing lava collected by drones. The team will use the observations from Hawai'i together with mathematical models of lava flows, analysis of samples collected from the flow, and laboratory experiments utilizing bubbly suspensions, to advance the ability to forecast how volcanic eruptions evolve and mitigate their hazards. In addition, the project will involve educators and students and produce educational materials based on the eruption, to promote science literacy and broaden participation. This is a project that is jointly funded by the National Science Foundation's Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own country (in this case, Durham University).

One of the challenges is that lava is a complex fluid that contains liquid melt, gas bubbles, and solid crystals, all acting together to determine the lava's behavior. This interaction changes during the advancement of the lava as crystals form, bubbles leave and the melt cools. This project will address this challenge by resolving two issues: 1) how multi-phase lava rheology evolves during emplacement; 2) how rheology impacts emplacement. The 2018 eruption at the Lower East Rift Zone of Kilauea Volcano in Hawaii (KLERZ) provides an opportunity to investigate lava emplacement in unprecedented detail. During the eruption, Unoccupied Aerial Systems (UAS) captured a uniquely comprehensive time-series of overhead videos of channelized lava. This study will create a new physical-mathematical framework for predicting lava flow emplacement based on new, quantitative understanding of the coupled evolution of lava rheology. We will leverage unprecedented, linked field data sets and combine them with analog experiments of channelized multi-phase flows and laboratory measurements of natural and analog mutliphase samples to investigate multi-phase rheology and flow at a range of length scales. This team will: 1) Perform laboratory rheometry and microstructure analysis of KLERZ samples; 2) Use UAS data to characterize the evolution of KLERZ channelized flows; 3) Used scaled lava analogues to construct and calibrate fundamental physical models; 4) Synthesize all observations to produce scale-sensitive rheological laws for KLERZ lavas; and 5) Integrate new rheological relations in existing flow emplacement models and test those on KLERZ flow field. The core deliverable of the proposed research will be a validated quantitative framework for predicting lava flow emplacement. This outcome is expected to improve assessment and mitigation of volcanic hazards. In addition, all numerical models and measurements from analog experiments will be made open, so that they can be used as benchmarks for future models. This study will enable scientists and practitioners to determine material properties and flow behavior of the natural system and, conversely, to use field observations of lava emplacement to deduce the properties of the lava.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.